"If I fight on in my campaign, all the way to the convention, I would forestall the launch of a national campaign and make it more likely that Senator Clinton or Obama would win. And in this time of war, I simply cannot let my campaign, be a part of aiding a surrender to terror," Romney will say at the Conservative Political Action Conference in Washington.

"This is not an easy decision for me. I hate to lose. My family, my friends and our supporters... many of you right here in this room... have given a great deal to get me where I have a shot at becoming President. If this were only about me, I would go on. But I entered this race because I love America, and because I love America."

McCain prevailed in most of the Super Tuesday states, moving closer to the numbers needed to officially win the nomination.

Overall, McCain led with 707 delegates, to 294 for Romney and 195 for Huckabee. It takes 1,191 to win the nomination at this summer's convention in St. Paul, Minn.

"I disagree with Senator McCain on a number of issues, as you know. But I agree with him on doing whatever it takes to be successful in Iraq, on finding and executing Osama bin Laden, and on eliminating al-Qaida and terror," Romney said.

Romney acknowledged the obstacles to beating McCain.

"As of today, more than 4 million people have given me their vote for president, less than Senator McCain's 4.7 million, but quite a statement nonetheless. Eleven states have given me their nod, compared to his 13. Of course, because size does matter, he's doing quite a bit better with his number of delegates," Romney said in prepared remarks.

Romney's departure from the race came almost a year after his formal entrance, when the Michigan native declared his candidacy on Feb. 12, 2007, at the Henry Ford Museum of Innovation in Dearborn, Mich.

Over the ensuing 12 months, Romney sought the support of conservatives with a family values campaign, emphasizing his opposition to abortion and gay marriage, as well as his support for tax cuts and health insurance that would benefit middle-class families.

"We need to teach our children that before they have babies, they get married," he told voters at his campaign events.

But he was dogged by charges of flip-flopping, a criticism that undermined the candidacy of another Massachusetts hopeful - John Kerry in 2004. In seeking to unseat Sen. Edward M. Kennedy in 1994, Romney said he would be a better advocate for gay rights than his rival and he favored abortion rights.

Throughout his campaign, Romney was questioned by voters and the media about his Mormon faith. Hoping assuage voters skeptical of electing a Mormon president, Romney gave speech on Dec. 6 in College Station, Texas, that explicitly recalled remarks John F. Kennedy made in 1960 in an effort to quell anti-Catholic bias. He vowed to serve the interests of the nation, not the church, if elected president.

In early voting Iowa, Romney sought votes by casting himself as the guardian of the Reagan-era conservative triad - a three-legged stool, as the candidate put it - of a strong national defense, strong economy and strong families.

Fueled by what would grow to more than $35 million of personal donations, his campaign hired top-notch staff in the early voting states, and Romney scored an early win when his organization topped the field at the Iowa Straw Poll in August.

By that time, the national front-runners, McCain and former New York Mayor Rudy Giuliani, had virtually ceded the lead-voting state to Romney.

Instead, McCain focused on New Hampshire, second on the calendar, while Giuliani employed an untested strategy of waiting out the early primary contests and instead staking his candidacy on a strong showing in the Jan. 29 Florida primary.

Romney's goal was to score back-to-back wins in Iowa and New Hampshire, clearing the field and creating momentum to roll through Florida - where he enjoyed the support of top aides to former Gov. Jeb Bush - and seal the nomination in the Super Tuesday contests.

Instead, Romney was beaten Jan. 3 in Iowa by former Arkansas Gov. Mike Huckabee, a former Southern Baptist minister who received an unexpected outpouring of support in the caucuses from voters identifying themselves as evangelicals.

Five days later, Romney suffered a second consecutive defeat in New Hampshire, when McCain won the primary in part with the support of independents attracted to his self-styled maverick campaign.

Romney, who headed the 2002 Winter Olympic Games in Salt Lake City, tried to cast each defeat in competitive terms, saying his second-place finishes amount to "silver medals." He also highlighted the "gold" he won in between and in the little-watched Wyoming caucuses.

Nonetheless, Romney took a cue from Huckabee's win, as well as Democrat Barack Obama's Iowa upset of rival Hillary Rodham Clinton, as a sign voters wanted change in Washington.

On the stump, he retooled his speech to harken back to the theme he broached in Dearborn, that America's future, and that of its government, were dependent on innovation. His campaign also hung new banners reading, "Washington is Broken," as well as a to-do list Romney would complete as president.

Romney and McCain went head-to-head in the Jan. 13 Michigan primary, and Romney won, in part by highlighting his background as a business consultant and venture capitalist. When McCain acknowledged what seemed to be obvious, that not all of Detroit's lost auto industry jobs would be recovered, Romney pounced.

He accused the senator of pessimism, outlining a $20 billion industry recovery package and telling audiences in economically ailing Michigan, "I will fight for every single job."

Romney also tweaked his stump speech to criticize McCain for stating that he was more familiar with foreign affairs and military matters than economic issues.

Highlighting his 25-year business career, he told audiences, "Senator McCain says the economy is not his strong suit; well, it is my strong suit."

As the calendar progressed, however, McCain picked up a big-ticket win in the Jan. 19 South Carolina primary. Romney instead focused on his victory in the Nevada caucuses the same day.

Ten days later, the two squared off again in the Florida primary, where McCain scored a major upset after winning endorsements from the state's two top elected Republicans - Gov. Charlie Crist, a popular figure who had previously said he planned to remain neutral in the race, and Sen. Mel Martinez.

The following day, Giuliani dropped out of the race and endorsed McCain. A day later, popular California Gov. Arnold Schwarzeneger announced his endorsement of McCain, reflecting a coalescing of Republican support behind the senator as he approached a Super Tuesday showdown with Romney.

Romney's final pitch was to label McCain a liberal like Clinton and Obama, a charge tantamount to heresy in the GOP. He was backed by conservative media voices like Rush Limbaugh and Ann Coulter.

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